The present invention relates generally to water drainage grate structures and deals more specifically with a trench grate.
Trench grates are generally relatively narrow, elongated structures that are used in driveways, parking lots and like paved surfaces to provide a supporting surface for vehicular traffic while permitting the collection of storm water run off into a subterranean basin. Typically, the grates are placed end-to-end in a linear fashion at the vehicular entrance and exists to the paved surfaces and also at other interior locations.
Conventional trench grates generally comprise two parts and are usually made of bar stock. One part is a frame generally having intersecting cross members which are welded to outer edge members of the frame and to one another to provide an integral structure. The second part generally receives the frame which generally nests in a recessed shoulder area of the receiving portion. The receiving portion is generally located in the upper surface area of the subterranean drainage structure. One drawback with conventional trench grates relates to the difficulty and time consumption required during fabrication since the cross members are generally held by a jig or other fixturing device while the intersections are welded and the ends of the cross members are welded to the inner face surfaces of the outer edge frame members.
A further drawback is the necessity of manufacturing the subterranean drainage structure with the metal frame receiving portion cast in the concrete. Such construction results in a more costly drainage structure and requires shipping the trench grate with the drainage structure.
Another drawback is the welds holding the intersection cross members tend to break with time whereby one or more cross members may break loose leaving a void in the trench grate which presents a hazardous condition to pedestrians and vehicles.
It is therefore a general aim of the present invention to provide an improved trench grate comprised of a single frame part that may be fabricated more easily than conventional trench grates and in a substanitally shorter time whereby it is not required to have a receiving portion cast in the drainage structure.
It is another aim of the invention to provide a trench grate wherein surface support is still provided in the event of a weld failure.